<template>
  <div class="app-container">
    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="最终发布"/>
    </el-steps>
    <el-form label-width="120px">
        <el-form-item label="课程标题">
            <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
        </el-form-item>

        <!-- 所属分类 TODO -->
        <el-form-item label="课程分类">
            <!-- 一级分类 -->
            <el-select v-model="courseInfo.subjectParentId" 
                    placeholder="请选择" @change="subjectLevelOneChanged">
                <el-option
                v-for="subject in subjectOneList"
                :key="subject.id"
                :label="subject.title"
                :value="subject.id"/>
            </el-select>
            <!-- 二级分类 -->
            <el-select v-model="courseInfo.subjectId" placeholder="请选择">
                <el-option
                v-for="subject in subjectTwoList"
                :key="subject.id"
                :label="subject.title"
                :value="subject.id"/>

            </el-select>
        </el-form-item>
        <!-- 课程讲师 TODO -->
        <el-form-item label="所属讲师">
            <el-select v-model="courseInfo.teacherId" placeholder="请选择">
                <el-option
                v-for="teacher in teacherList"
                :key="teacher.id"
                :label="teacher.name"
                :value="teacher.id"/>

            </el-select>
        </el-form-item>

        <el-form-item label="总课时">
            <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
        </el-form-item>

        <!-- 课程简介 TODO -->
        <el-form-item label="课程简介">
            <!-- <el-input v-model="courseInfo.description" placeholder=" "/> -->
            <tinymce :height="300" v-model="courseInfo.description"/>
        </el-form-item>


        <!-- 课程封面 TODO -->
        <!-- 课程封面-->
        <el-form-item label="课程封面">

            <el-upload
                :show-file-list="false"
                :on-success="handleAvatarSuccess"
                :before-upload="beforeAvatarUpload"
                :action="BASE_API+'eduoss/fileoss'"
                class="avatar-uploader">
                <img :src="courseInfo.cover">
            </el-upload>

        </el-form-item>


        <el-form-item label="课程价格">
            <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
        </el-form-item>

        <el-form-item>
            <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
        </el-form-item>
    </el-form>
  </div>
</template>

<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce' //引入富文本编辑器
export default {
    components: { Tinymce },
    data () {
        return {
            saveBtnDisabled : false,
            courseInfo : {
                title: '',
                subjectId: '',//二级分类id
                subjectParentId:'',//一级分类id
                teacherId: '',
                lessonNum: 0,
                description: '',
                cover: '/static/01.jpg',//默认课程封面
                price: 0
            },
            courseId : '',
            BASE_API : process.env.BASE_API,
            teacherList : [],
            subjectOneList : [], //一级分类列表
            subjectTwoList : [] //二级分类
        }
    },
    created() {
        if (this.$route.params && this.$route.params.id) {
            this.courseId = this.$route.params.id
            this.getCourseInfo()
        } else {
            this.getTeacherList()
            this.getSubjectOneList()
        }
    },
    watch: {  //监听
        $route(to, from) { //路由变化方式，路由发生变化，方法就会执行
            this.init()
        }
    },
    methods: {
        init() {
            this.courseInfo = []
        },
        //根据course_id获取信息
        getCourseInfo() {
            course.getCourseInfo(this.courseId)
                .then(response => {
                    this.courseInfo = response.data.courseInfoVo
                    //为subjectTwoList赋值
                    //回显一级分类和二级分类
                    subject.getAll()
                        .then(response => {
                            this.subjectOneList = response.data.list
                            for (let i = 0; i < this.subjectOneList.length; i++) {
                                if (this.subjectOneList[i].id === this.courseInfo.subjectParentId) {
                                    this.subjectTwoList = this.subjectOneList[i].children
                                }
                            }
                        })
                    //查询所有讲师(为了回显讲师)
                    this.getTeacherList()
                })
        },
        //图片上传成功的回调
        handleAvatarSuccess(response, file) {
            console.log('file ', file)
            this.courseInfo.cover = response.data.url //阿里云OSS的图片地址
        },
        //图片上传之前的回调
        beforeAvatarUpload(file) {//检验图片格式
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2

            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }
            return isJPG && isLt2M
        },
        //获取讲师列表
        getTeacherList() {
            course.findAll()
                .then(response => {
                    this.teacherList = response.data.items
                })
        },
        //获取一级分类
        getSubjectOneList() {
            subject.getAll()
                .then(response => {
                    this.subjectOneList = response.data.list
                })
        },
        //点击某个一级分类，触发change，显示对应二级分类
        //这个value就是选中的值
        subjectLevelOneChanged(value) {
            for (let i = 0; i < this.subjectOneList.length; i++) {
                if (value === this.subjectOneList[i].id) {
                    this.subjectTwoList = this.subjectOneList[i].children
                    //选中一级列表之后清空二级列表的数值
                    this.courseInfo.subjectId = ''
                }
            }
        },

        //添加课程
        addCourse() {
            course.addCourseInfo(this.courseInfo)
                .then(response => {
                    this.$message({
                    type: 'success',
                    message: '添加课程信息成功'
                })
                    this.$router.push({path:'/course/chapter/' + response.data.courseId})
                })
        },
        //修改课程
        updateCourse() {
            course.updateCourseInfo(this.courseInfo)
                .then(response => {
                     //提示
                    this.$message({
                        type: 'success',
                        message: '修改课程信息成功!'
                    });
                    //跳转到第二步
                    this.$router.push({path:'/course/chapter/'+this.courseId})
                })
        },

        saveOrUpdate() {
            if (this.courseInfo.id) {
                this.updateCourse()
            } else {
                this.addCourse()
            }
        }
    },
}
</script>
<style scoped>
    .tinymce-container {
        /* 调整上传图片按钮的高度 */
        line-height: 29px;
    }
</style>